Talk at Dublin Core Libraries Community (Sep 5, 2013 in Lisbon). Includes a first draft of a version history for SKOS files - see project on https://github.com/jneubert/skos-history

1. Constantly Under Construction STW Thesaurus for Economics Linked Data Maintenance
Joachim Neubert
ZBW – Leibniz Information Centre for Economics
DCMI Libraries Community
DC-2013, Lisbon, Portugal
05.09.2013
ZBW is member of the Leibniz Association

2. STW Thesaurus for Economics



Created in the 1990s, currently maintained and enhanced by ZBW
More than 6,000 descriptors in English and German
Fine-meshed network of concepts:
 More than 16,000 broader/narrower relations
 11,000 related concepts
 Additional access path through a term classification with more
than 500 entries
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3. STW versions and changes against the previous
8.04 – 29.2.2009
 223 new descriptors (skos:Concept with skos:prefLabel de/en)
 4 deleted descriptors
 618 new non-descriptors (skos:altLabel)
8.06 – 22.4.2010
 58 new descriptors
 57 deleted descriptors
 491 new non-descriptors
8.08 – 30.6.2011
 105 new descriptors
 141 deleted descriptors
 1490 new non-descriptors
8.10 – 21.3.2012
(Counts stem from the legacy maintenance system and may not be as accurate as they seem, but should give an idea about
the change frequency)
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4. Other kinds of changes
Other kinds of changes may be highly relevant especially for the
creation and evolvement of mappings from or to other vocabularies:
 Changes of the preferred label
„Partnership“ -> „Business partnership“
 Changes of alternative labels
„Bankkonkurs“ -> „Bankenkonkurs“
 Changes of relations (broader/narrower/related)
 Labels attached to new concepts
„Industrial cluster “ from „Geographic concentration “ (deleted) to
„Regional Cluster “
 Splits and merges of concepts
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5. How do we currently handle this?
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6. RDF statements about a particular version
<http://zbw.eu/stw>
a skos:ConceptScheme, void:Dataset ;
dcterms:issued "2012-03-21"^^xsd:date ;
owl:versionInfo "8.10" ;
...
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7. STW URI versioning concept
Stable URIs for skos:ConceptScheme und skos:Concept
 http://zbw.eu/stw
 http://zbw.eu/stw/descriptor/19664-4
303 redirect to versioned URLs (RDFa files, when required with language
extension)
 http://zbw.eu/stw/versions/latest/about
 http://zbw.eu/stw/versions/latest/descriptor/19664-4/about
Archived RDFa/rdf/ttl files available (with hint to the latest version)
 http://zbw.eu/stw/versions/8.06/about
 http://zbw.eu/stw/versions/8.06/descriptor/19664-4/about
Search functions and web services always work on the latest version
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8. Pragmatic solution – overview page
Changes are traceable
only intellectually (but
at all)
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9. Detailed changelog
From legacy maintance system (simple text file, in German):
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10. Deleted descriptors/concepts
URI is still defined – shown on a RDFa page like this:
<http://zbw.eu/stw/descriptor/12257-3>
a skos:Concept, zbwext:Descriptor ;
skos:inScheme <http://zbw.eu/stw> ;
rdfs:label "Real estate loan"@en, "Realkredit"@de ;
owl:deprecated true ;
dcterms:isReplacedBy <http://zbw.eu/stw/descriptor/13775-4> ;
skos:historyNote "Deprecated (used at last in version
8.04)"@en .
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11. How to handle this better?
What users want to know when we publish a new version:
 What‘s new?
 What has changed?
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12. Rough plan for a SKOS history
1) Create a raw diff of sorted n-triple files. (This gives you thousands
and thousends of differences, even excluding bnodes.)
2) Group changes for each concept.
3) Recognize insertion and deletion of concepts as a whole
(presumably the most important changes).
4) Recognize certain types of changes (e.g., altered prefLabel, added
altLabel, changed relations).
5) Enrich the concept URIs with the preferred label (in a given
language).
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13. Rough plan for a SKOS history (continued)
6) Arrange everything nicely on a RDFa overview page
(additions/deletion of concepts, perhaps some of the more important
types of changes, statistics such as amount of changed/unchanged
concepts, etc.)
7) Provide a change history per concept, e.g. on a RDFa page which
can be linked from a concept page.
8) Optionally, if the terminology includes meta-structures such as a
subject classification, add aggregated information about the most
intensively changed subject areas (hot spots) to the overview page.
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14. URIs for versions and version deltas
URI for version, e.g.
named graphs
 http://zbw.eu/stw/version/8.04
URI for delta, e.g.
 http://zbw.eu/stw/version/8.04/delta/8.06
Each delta has a deletions and a insertions part, e.g.
 http://zbw.eu/stw/version/8.04/delta/8.06/insertions
 http://zbw.eu/stw/version/8.04/delta/8.06/deletions
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15. History of a SKOS concept
Implementation prototype based on version and delta files, loaded as
named graphs into a SPARQL endpoint. Example CONSTRUCT result:
<http://zbw.eu/stw/descriptor/10112-4>
skos:prefLabel "Welfare analysis"@en , "Wohlfahrtsanalyse"@de ;
:history [ :altLabelDeltion "Wohlfahrtsmessung"@de , "Wohlfahrtsmaß"@de , "Welfare measurement"@en , "Wohlstandsmaß"@de ;
:altLabelInsertion "Welfare effect"@en , "Wohlfahrtsgewinn"@de , "Wohlfahrtseffekt"@de , "Wohlfahrtsverlust"@de ;
:delta
<http://zbw.eu/stw/version/8.08/delta/8.10> ;
:prefLabelDeletion "Welfare effect"@en , "Wohlfahrtseffekt"@de ;
:prefLabelInsertion "Wohlfahrtsanalyse"@de , "Welfare analysis"@en
].
(Very preliminary implementation, currently limited to prefLabel and altLabel changes)
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16. Thanks
Joachim Neubert
ZBW – Leibniz Information Centre for Economics
j.neubert@zbw.eu
http://zbw.eu/stw
http://zbw.eu/labs
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